Structural and dosimetric study of sub-kGy neutron-irradiated graphitic media

• Main Authors: Nawi, Siti Nurasiah Mat, Khandaker, Mayeen Uddin, Sani, S. F. Abdul, Ismail, S. S., Al-Mugren, K. S., Islam, Mohammad Amirul, Naher, Kamrun, Bradley, D. A.
• Format: Article
• Published: Pergamon-Elsevier Science Ltd 2021
• Subjects: QC Physics; QD Chemistry
• Online Access: http://eprints.um.edu.my/34112/

Associated with the marked difference between the mechanism of neutrons interactions relative to that of low linear-energy transfer (LET) radiations, few convenient dosimeters offer well differentiated measurement of neutron doses at useful sensitivity and spatial resolution. Present study has made use of highly uniform 2B and HB grade polymer pencil lead graphite (PPLG) (approximately 95 wt % and 61 wt % graphite content, respectively), addressing variation in lattice structure and defects resulting from sub-kGy neutron-doses. The latter have been provided by the TRIGA-II nuclear reactor located at the Bangladesh Atomic Energy Commission. Raman, photoluminescence (PL), and thermoluminescence (TL) techniques were used to perform structural and luminescence characterization of PPLGs. Comparison was made with highly-oriented pyrolytic graphite (HOPG), a pure ordered synthetic form of graphite. The dose-dependent defects produced in graphitic structures were characterized based on the Raman ID/IG intensity ratio, with observation of the Wigner effect. Analysis of PL spectra provides an average band gap energy in the range of 1.111-1.114 eV. All samples have been found to provide excellent linear response within the dose range 0-200 Gy, 2B grade PPLGs showing greater sensitivity compared to that of HB. The outcomes from this research may contribute to the development of cost effective, versatile graphite-based dosimeters, with particular applications to ionizing radiation dosimetry in clinical radiotherapy and industrial spheres.